Guinier–Preston Zones Featuring PtCu Nanocrystals:\nCoherency Strain Fields Reshaping the Band Structure for Oxygen Reduction\nElectrocatalysis

Microstructurally\ndistorted Pt-based nanoalloys with unusual structural\ndefects like Guinier–Preston (GP) zones with in situ coherency\nstrain fields may be suitable for substantially improving their electrocatalytic\nperformance for the oxygen reduction reaction (ORR) in acidic conditions.\nHerein, GP zones contributing PtCu nanoalloys were first fabricated\nby additive manufacturing, starting with the formation of metallic\nCu clusters as orderly crystal nuclei on ZIF-8-derived carbon, followed\nby the additive manufacturing of chemically reduced Pt and Cu on the\nformed clusters in ethylene glycol at 190 °C. The atomic-scale\nGP zones give rise to high-level coherent strain fields across the\nnanocrystals, boosting the ORR kinetics. This catalyst exhibits an\nultrahigh oxygen reduction half-wave potential of 0.934 V (vs RHE)\nand a mass activity (MA) of 0.68 A mg<sub>Pt</sub><sup>–1</sup>. After the accelerated degradation test of 50,000 cycles, the achieved\nMA improved instead of decreasing, rising from 0.68 to 0.89 A mg<sub>Pt</sub><sup>–1</sup>, surpassing that of commercial Pt/C\nsignificantly. The significantly improved activity is attributed to\nthe coherency strain fields reshaping the band structure and reconstructing\na favorable charge density for active Pt sites. Importantly, the interface-anchored\nGP zones, maintaining a completely coherent relationship with the\nmatrix, can effectively impede metal atom migration, segregation,\nor leaching, thus enhancing long-term stability. Therefore, the novel\nGP-type alloys may pave another way for designing advanced catalysts\nin the realm of current energy storage and conversion fields like\nfuel cells.